make every tab have its own filter settings
make every tab have its own filter settings

The tree filters for files/hidden-files/bookmarks now operate off tab
local variables which default to the global variables when a nerd tree
is initialised in the tab. Note: the file-filter already operated in
this way.

This means that each tree/tab has its own filter settings that are
initialised to the users preferences as specified by the global
variables, but can be altered independently of the other trees/tabs

tschundler/dotfiles,tschundler/dotfiles,tschundler/dotfiles,iff/dotfiles-old,iff/dotfiles-old,nywilken/dotfiles,nywilken/dotfiles